Sealing means for a vacuum gripping device



Nov. 23, 1965 v. H. AMES SEALING MEANS FOR A VACUUM GRIPPING DEVICE 6Sheets-Sheet 1 Filed July 1, 1963 R TE N U0 M m .JH R m m 4 W m Y B .N.W 9 J i fiqw m Nov. 23, 1965 v. H. AMES 3,219,379

SEALING MEANS FOR A VACUUM GRIPPING DEVICE Filed July 1, 1963 6Sheets-Sheet 2 INVENTOR. VICTOR H. AMES Nov. 23, 1965 v. H. AMES SEALINGMEANS FOR A VACUUM GRIPPING DEVICE 6 Sheets-Sheet 3 Filed July 1, 1963INVENTOR. VICTOR H AMES NOV. 23, 1965 v, H ME SEALING MEANS FOR A VACUUMGRIPPING DEVICE Filed July 1, 1963 6 Sheets-Sheet 4 81 68 #8 37 @flttys.

97 INVENTOR. 97a VICTOR H. AMEs Nov. 23, 1965 v. H. AMES 3,219,379

SEALING MEANS FOR A VACUUM GRIPPING DEVICE Filed July 1, 1963 6Sheets-Sheet 5 13,g VACUUM INVENTOR. VICTOR H AMES Nov. 23, 1965 v. H.AMES SEALING MEANS FOR A VACUUM GRIPPING DEVICE Filed July 1, 1963 6Sheets-Sheet 6 INVENTOR. VICTOR H. AMES United States Patent 3,219,379SEALING MEANS FOR A VAfIUUM GRIPPING DEVICE Victor H. Amos, Midlothian,Ill., assiguor to Whiting Corporation, a corporation of Illinois FiledJuly 1, 1963. Ser. No. 291,654 6 Claims. (Cl. 294-64) This inventionrelates to material handling equipment and more particularly to a newand improved vacuum gripping device for lifting an object by applicationof one or more vacuum pads to the surface of the object.

Known vacuum gripping and lifting devices of the type including one ormore vacuum pads mounted on a movable support have been provided withmeans adapting the pads to grip a surface automatically upon engagementwith the same. Such means have included devices in the nature ofmechanically operating feeler arms located adjacent the vaccum pads fordetecting the presence of a surface to be gripped. This inventionprovides a vacuum gripping device including one or more vacuum grippingpads wherein each pad is provided with pneumatic means adapting each padfor automatically gripping a particular surface upon contact of the paditself with the surface.

A primary object of the present invention is the provision of a vacuumgripping device including a new and improved vacuum gripping padassembly having pneumatic means adapting the pad to grip a particularsurface automatically upon contact with the same.

Another object of the present invention is the provision of a vacuumgripping device including a plurality of separate vacuum gripping padassemblies wherein each assembly has pneumatic means adapting the pad togrip a particular surface independently and automatically upon contactwith the same.

Still another object of the present invention is to provide a vacuumgripping device for a lift truck, which device includes a plurality ofseparate vacuum pad assemblies in communication with a source of vacuumcarried by the truck, wherein each vacuum pad assembly has pneumaticmeans adapting the pad to grip a particular surface independently andautomatically upon contact with the same and wherein means are providedfor simultaneously breaking communication with all of the vacuum padassemblies and the source of vaccum.

Even another object of the present invention is the provision of avacuum gripping device including a plurality of vacuum pad assemblieseach of which assemblies is adapted to grip a particular surfaceautomatically upon contact with the same, wherein each vacuum padassembly includes improved means for quickly releasing the surfacegripped.

Another object of the present invention is to provide a vacuum grippingdevice including at least one vacuum pad assembly, wherein each padassembly includes a vacuum pad and improved sealing means therefor foreffecting a seal between the pad and a surface to be gripped, whichsealing means is adapted to accommodate wrinkles or irregularities inthe surface gripped.

Yet another object of the present invention is the provision of a vacuumgripping device including at least one vacuum pad assembly adapted foreffectively gripping curved surfaces.

These and other objects and advantages of the invention will becomeapparent from the following specification wherein like numerals refer tosimilar parts throughout.

In the drawings:

FIG. 1 is a front elevation of one embodiment of the vacuum grippingdevice of this invention showing the same mounted on the carriage at thefront end of an industrial lift truck;

FIG. 2 is an enlarged rear elevation of the pair of elongated dualvacuum pad plates of the vacuum gripping device of FIG. 1, the supportfor the plates being shown 1n phantom lines;

FIG. 3 is an enlarged fragmentary front elevation of one of the vacuumpad plates showing one of the vacuum pad assemblies;

FIG. 4 is an enlarged partial section and partial elevation taken alongline 44 of FIG. 3;

FIG. 5 is an enlarged central longitudinal section taken through one ofthe separate valve members associated with each vacuum pad assemblyshowing the valve member in its condition before a surface is gripped;

FIG. 6 is a fragmentary section similar to FIG. 5 showing the valvemember in its condition after a surface has been gripped;

FIG. 7 is a section taken along line 77 of FIG. 6;

FIG. 8 is a section taken along line 88 of FIG. 6;

FIG. 9 is a fragmentary section taken along line 99 of FIG. 6;

FIG. 10 is a schematic view of a vacuum producing and control system forthe embodiment of the invention shown in FIG. 1;

FIG. 11 is a section similar to FIG. 5 showing a modified valve member;

FIG. 12 is a schematic view of a vacuum producing and control systememploying the modified valve members; and

FIG. 13 is a schematic view of a modified vacuum pad assembly.

Briefly, and by way of introduction, the vacuum gripping device of thisinvention includes at least one vacuum pad assembly mounted on a movablesupport. The vacuum pad assembly, which is specially designed forgripping a curved surface, includes a vacuum pad having a main vacuumport, a separate pilot vacuum port adjacent the main port and a valvearrangement associated with the pad and in communication with bothports, the valve arrangement being adapted to be placed in communicationwith a source of vacuum. The pilot vacuum port has a pilot cup memberassociated therewith providing for closing of the pilot vacuum port by aparticular surface to be gripped upon contact of the rim of the cup withthe surface. The rim of the pilot cup is preferably inwardly ofisetWithin the pad sealing ring for being contacted by a surface to begripped after the pad sealing ring has made its initial contact with thesurface. Closing of the pilot vacuum port results in actuation of avalve member for applying a vacuum to the vacuum pad and therebygripping the surface contacted. In other words, the vacuum pad assemblyof this invention, includes penumatic means adapting the pad to grip asurface automatically upon contact of only the pad assembly itself withthe surface. This invention also includes the provision of mounting aplurality of vacuum pad assemblies in generally co-planar relationshipon a movable support member. Separate valve members and pilot cups areprovided for each vacuum pad assembly adapting each assembly forindependently and automatically gripping a particular surface uponcontact with the same. Means are also provided for simultaneouslybreaking communication between the source of vacuum and all vacuum padassemblies for release of the surface or surfaces gripped, and theinvention includes means for accomplishing this release in a quickmanner.

The embodiment of the invention shown for purposes of illustration isassociated with an industrial lift truck of known type and is especiallydesigned for handling large rolls of newsprint. It will be realized thatthe vacuum gripping device of this invention may be mounted on any typeof material handling equipment, such as a crane,

for example. The vacuum gripping device shown is in the form of aplurality of separate vacuum pad assemlies mounted on a support which isin turn movably mounted on the carriage of the industrial lift truck.Two vacuum pad assemblies are provided on each of a pair of parallelelongated vacuum pad plates, and each plate is transversely curved andpivotally mounted on the support for limited swinging movement about thelongitudinal axis of the plate for accommodating the curvature of thepaper roll to be gripped. The entire support is adapted for rotationabout a horizontal, front-to-rear central axis, and the carriagemounting the support is adapted for vertical reciprocatory movement. Thearrangement is such that a roll of paper may be gripped by the vacuumdevice and handled or manipulated as desired by any combination ofmovements of the support, carriage and lift truck. By virtue of theautomatic operation of the vacuum pad assemblies of this invention anarticle to be handled, such as a paper roll, will be automaticallygripped by contact of the vacuum pad assemblies with the surface of thearticle. By reason of the independent operation of each vacuum padassembly, a vacuum is applied to a particular vacuum pad assembly onlywhen that assembly is brought into contact with the surface of thearticle. Therefore, if only two vacuum pad assemblies in the embodimentof the vacuum gripping'device illustrated should be brought into contactwith a paper roll, for example, a vacuum would be applied only to thesetwo assemblies. The invention also includes improved means forsimultaneously breaking communication between the source of vacuum andall of the vacuum pad assemblies for release of a surface or surfacesgripped, and the invention includes improved sealing means for thevacuum pad assemblies for forming an effective seal with the surface ofan object, such as a paper roll, which object may have wrinkles orirregularities in its surface.

Now referring to the drawings and more particularly to FIGS. 1 and 2, anembodiment of the vacuum gripping device, generally designated 10, willbe seen to include primarily a pair of elongated dual vacuum padassembly plates 11 and 12, each of which plates is slightly curved intransverse cross-section for gripping the curved surface of acylindrical object. Plate 11, which includes two vacuum pad assembliesgenerally designated 14 and 15, is pivotally mounted to a generallysquare support member 16 for limited swinging movement about thelongitudinal axis of the plate. Similarly, plate 12, which includes twovacuum pad assemblies generally designated 18 and 19, is pivotallymounted to support 16 for limited swinging movement about thelongitudinal axis of the plate. In the embodiment of the invention shownfor purposes of illustration, the vacuum griping device of thisinvention is movably mounted on a known type of industrial lift truck,generally designated 20, for gripping and handling large rolls of paperof the type use in printing newspapers. Plates 11 and 12 are pivotallymounted on support 16 for accommodating the curvature of a paper rollwhich varies to some degree depending on, of course, the size -of theroll. While each plate may be pivotally mounted to support 16 by anysuitable means, each plate is preferably provided with upper and lowerpairs of integral apertured ear plates 21and 22, respectively. It willbe understood that the pairs of ear plates are adapted to receive pinsheld in lugs or the like (not shown) extending from support 16 forproviding pivotal mounting of the plates to the support. Support 16,which of itself forms no part of the present invention, may be of anysuitable construction for mounting plates 11 and 12 on a carriage (notshown) on lift truck 20 for swinging movement in a vertical plane, i.e.support 16 is adapted for rotation about a central horizontal axisextending longitudinally of the truck allowing a vertically extendingpaper roll, for example, to be gripped by vacuum gripping device 10and-swung or rotated in a vertical plane.. Preferably, hydraulic meansare provide-d for rotating or swinging support 16.

It will be understood that lift truck 20, which forms no part of thepresent invention and may be of any known type, includes stationaryparallel upright members 24 and 25 slidably supporting movable parallelupright members 26 and 27, respectively. Uprights 26 and 27 support acarriage (not shown) and vertical reciprocatory movement is imparted touprights 26 and 27 by means of a hydraulic ram 28 having a pair oflifting chains 29 and 30 associated therewith. A number of pulleys 32and 33 are suitably supported by a head member attached to thestationary uprights for supporting various vacuum and hydraulic lines 34and 35, respectively,extending to support 16; Vacuum line 34 has one endthereof in communication with a swivel 37 of known construction forcommunicating a source of vacuum carried by the truck with all of thevacuum pad assemblies.

As best seen in FIG. 2, vacuum pad assemblies 14, 15, 18 and 19 includevalve members 40, 41, 42 and 43, respectively. Valve members 40 and 41are in respective communication with vacuum lines 44 and 45, whichvacuum lines communicate with a T-member 46. T-member 46 communicateswith swivel 37 by means of a vacuum line 47. Similarly, valve members 42and 43 communicate with vacuum lines 48 and 49, respectively, whichlines connect with a T-member 50. T-member 50 is in communication withswivel 37 by means of a vacuum line 51. It will be understood thatswivel 37 provides constant communication between line 34 and lines 47and ,51 regardless of the disposition of support 16 with respect to thelift truck carriage. As will be explained in'greater detail hereinbelow,the valve members, among other things, serve to communicate all vacuumpad assemblies with a common source of vacuum and adapt each vacuum padassembly for independent and automatic gripping of a surface. As eachvacuum pad assembly is of identical construction, it will suffice forpurposes for understanding the invention to describe only on .acylindrical object to be gripped; As seen in FIG. 4,

pad includes a rearwardly offset marginal portion 55a having continuous,parallel, inner and outer grooves 57 and 58 formed therein. Sealingmember 56 includes a generally U-shaped flexible sealing ring 59having'inner and outer'lip portions 60 and 61 adapted to be received inrespective grooves 57 and 58 and held therein by means of aretainer'ring 62, which retainer ring is secured to pad portion 55a bymeans of a plurality of bolt means 63 spaced apart around the peripheryof pad 55. Sealing ring member 59 is preferably made of neoprene. Acontinuous resilient ring member 65 is disposed within flexible'ringmember 59 and held therein in contact with retaining ring 62 by means ofa suitable adhesive. Resilient ring member 65 is preferably made of aclosed cellular sponge-like material having a degree of resiliencysomewhat firmer than that of sponge rubber. As noted in FIG. 4, thebight portion of flexible ring member 59 -is in spaced relation with theoutermost portion of resilient ring member 65 for defining a continuousclearance space therebetween.

As is known to those skilled in the art, it is quite difficult to forman effective seal between a vacuum pad and a curved surface to begripped, e.g., a roll of a material or a pipe section, because ofleakage at the marginal portions of the pad, The vacuum pad of thisinvention provides an extremely effective seal with a curved surface bymeans of the curved or arcuate pad and the sealing member secured to themarginal portion thereof. Sealing member 56 has been found to be quiteeffective in forming a secure seal between pad and the curved surface ofan object to be gripped thereby, such as the surface of a roll of paperof the type used in printing newspapers. Frequently, such paper rollshave slight irregularities or wrinkles in the contour of the surfacethereof. Curved pad 55, which is curved along one axis thereof, allowsthe sealing ring to accommodate the curved surface, and sealing ring 56readily adapts itself for forming a seal along any wringles orirregularities in the curved surface. Flexible ring member 59 readilyflexes and conforms to the contour of the surface of a paper roll to begripped for forming a seal between the surface and pad 55 shortly afterinitial contact between ring member 59 and the paper roll. As pad 55 isvacuumized drawing the same into closer contact with the surface of thepaper roll to be gripped, flexible ring member 59 continues to flex ordeform after it is brought into contact with resilient ring member 65.The latter ring member acts as a backup or resilient support for ringmember 59. Continued vacuumizing of pad 55 results in both ring membersbeing squeezed or compressed until the surface of the paper roll isbrought into contact with friction pads 66, which friction pads arespaced one at each corner of pad 55. Further, sealing ring 56 readilyadapts itself to accommodate the shape of the marginal portion of pad 55to which it is attached. Because of the curvature of pad 55 along oneaxis thereof, two opposite marginal portions of the pad are straight,two other marginal portions of the pad are curved at a certain radiusand the four corners of the pad are curved at a different curvature forsmoothly joining the marginal portions of the pad. Ring members 59 andreadily conform to these surfaces of the pad. The clearance spacebetween these two ring members is suflicient for insuring their spacedrelationship with each other along the entire lengths of the members.

Vacuum pad 55 will be seen to include a generally centrally disposed,inwardly offset portion 55b in which is formed a main vacuum port 68 anda pilot vacuum bore 69, which bore is internally threaded for threadingengagement with the external threads of an insert member 70. Insert 70is centrally bored defining a pilot vacuum port 72, and the insertincludes an annular flange portion 73 adapted to be received within anannular recess 74 formed in the base portion of a centrally aperturedpilot cup 75 for holding the latter in sealing engagement with padportion 55b around bore 69 therein. The purpose and function of pilotcup 75, which is preferably made of a flexible material such as gumrubber, will be explained hereinbelow.

Referring now to FIGS. 5 and 6, it will be seen that valve member 40having a main vacuum opening and a pilot vacuum opening 81 is secured tothe backside of pad portion 55b with openings 80 and 81 in respectivealignment with ports 68 and 72. A gasket member 82 having a pair ofopenings adapted for respective alignment with openings 80 and 81 isprovided for forming an air-tight seal between the openings in the valvemember and the ports in the pad. Preferably, a flat screen (not shown)is held in place against one face of the gasket for covering openings 80and 81 to prevent entry of foreign matter into the various bores andpassageways in valve member 40. Valve member 40 includes a central bore85 having annular passageways 86, 87, and 88 opening into the bore andspaced-apart along the longitudinal axis of the same. Bore 85 is closedat one end thereof by means of a cover plate 90 secured to one end ofthe body member by a plurality of bolts 91. The cover plate is insealing engagement with the body member by means of a gasket 92. Asecond cover plate 94 is secured to the other end of the body member bya plurality of bolts 95, which cover plate is in sealing engagement withthis end of the body member by means of a gasket 96. Cover plate 94includes an aperture 97 having an internally threaded tapered portion97a and a transversely extending recess 98 communicating with aperture97. Aperture portion 97a is adapted for threadingly receiving a threadedstud portion 99 of an air breather member 100. Air breather 100, whichis of known construction, includes suitable screened openings (notshown) for communicating the interior of hollow stud portion 99 with theatmosphere. In other words, the end of bore 85 adjacent cover plate 94is always open to atmosphere through aperture 97 and breather 100. Valvemember 40 includes a pair of side bores 102 (FIG. 9) adapted forregistry with opposite ends of recess 98, which side bores are incommunication with annular passageway 88. As noted in FIG. 8, gasket 86includes an opening 103 shaped for allowing communication betweenopposite ends of recess 98 and side bores 102. It will be realized thatannular passageway 88 is always open to atmosphere by means of sidebores 102, recess 98, opening 97 and air breather 100.

A valve spool 105 is adapted to be slidably received within bore 85 foraxial reciprocatory movement therein, and the valve spool is normallybiased away from the end of the bore defined by cover plate 90 by a coilspring 106 for defining a chamber in the bore. One end of spring 106 isadapted to be received in a central bore 105a formed within the valvespool, and the other end of the spring is adapted to be received in acentrally disposed recess 107 formed on the inside face of cover plate90.

An axially extending passageway 108 having a constricted portion 108aopening into annular passageway 86 is provided in valve member 40.Passageway 108 opens along the length thereof into opening 81, and theend of passageway 108 remote from the constricted portion opens at theend of valve member 40 adjacent cover plate 90. Gasket 92 maintainscover plate 90 in spaced relation with the end of the valve memberadjacent this cover plate, and gasket 92 is provided with a centralopening 109 (FIG. 7) shaped for exposing the end of passageway 108.Accordingly, this end of bore 85 adjacent cover plate 90 is always incommunication with pilot vacuum port 72 and annular passageway 86 bymeans of passageway 108 as long as valve spool 105 is held in its normalposition by spring 106, i.e., held out of contact with cover plate 90 bythe spring. As noted in FIG. 7, a passageway 111 is formed in valvemember 40 for communicating vacuum line 44 with annular passageway 86.

Referring again to FIG. 5, valve spool 105 includes a reduced indiameter annular portion 105b along the length thereof for placingannular passageways 87 and 88 in communication with each other whenvalve spool 105 is in its spring biased position, i.e., to the right asseen in FIG. 5. As annular passageway 87 communicates with opening 80which in turn communicates with main vacuum port 68, the latter opens toatmosphere through breather when spool is in the position shown in FIG.5.

The operation of vacuum pad assembly 14 is as follows:

Vacuum line 44 is placed in communication with a suitable source ofvacuum which results in a flow of air from atmosphere through pilotvacuum port 72, opening 81, passageway 108 including constricted portion108a, annular passageway 86 and passageway 111. As constricted portion108a of passageway 108 has a relatively small diameter, this flow of airfrom atmosphere is not substantial. Constricted portion 108a performs avery important function during this stage of operation of valve 40.Because of the relatively small diameter of portion 108a, a substantialvacuum is maintained in annular passageway 86 notwithstanding the factthat passageway 86 is opened to atmosphere by means of passageway 108including portion 108a, opening 81 and pilot vacuum port 72. Also, byreason of the relatively small diameter of passageway portion 108a, thechamber in bore 85 adjacent the forward end of the valve spool ismaintained at substantially atmospheric pressure notwithstanding thecommunication of this chamber with vacuumized chamber 86 via passageway108 including constricted portion 108a. Or in other Words, because ofthe relative sizes of constricted portion 108a and opening 81 which hasa much greater diameter than portion 108a and which communicates withthe pilot vacuum port, the chamber in bore 85 adjacent the front end ofthe valve stem remains substantially at atmospheric pressure when avacuum is being drawn through annular passageway 86. By reason of thesize and construction of constricted portion 108a and the associatedpassageways, there is a substantial pressure drop or pressure variancebetween annular passageway 86 and the chamber defined in bore 85 betweencover plate 90 and the valve spool. Accordingly, when cup 75 is closedwith the surface of an object to be gripped thereby closing the pilotvacuum port and closing bore 85 from the atmosphere, this pressure dropcauses the valve spool to be quickly and smartly snapped to the left asseen in FIG. 5. It is desirable to provide constricted portion 108a withthe smallest diameter possible to achieve the greatest possible pressuredrop between bore 85 and annular passageway 86. On the other hand,constricted portion 108a should not be made so small that clogging ispossible or that an unacceptable length of time will be required forvacuumizing the chamber in bore 85 for initiating movement of the valvespool.

In the normal or spring biased position of valve spool 105, i.e., theposition of FIG. 5, there is no flow :of air through the main vacuumport due to operation of the source of vacuum as annular passageways 86and 87 are prevented from communicating with each other by the valvespool. As vacuum pad 55 is brought into contact with the surface of anobject to be gripped, flexible ring member 59 flexes allowing thesurface of the object and pad 55 to be brought together until thesurface of the object is contacted by the rim portion of pilot cup 75.The rim portion of the pilot cup readily conforms to the surface of theobject to be gripped resulting in closing the pilot vacuum port therebypreventing the flow of air through this port to the source of vacuum andbreaking communication between bore 85 and the atmosphere. As explainedabove, closing of the pilot vacuum port results in vacuumizing of thechamber in bore 85 adjacent the forward end of the valve spool by virtueof the communication of this portion of the bore with the source ofvacuum by means of passageway 108 including the constricted porton 108a,annular passageway 86 and passageway 111. When the pressure in thischamber of bore 85 drops sufliciently for allowing atmospheric pressureacting on the end of the valve spool adjacent cover plate 94 (it will berecalled that this end of the valve spool is open to atmosphere throughbreather 100) to overcome the force of spring 106, valve spool 105 willbe moved in bore 85 until the spool contacts cover plate 90 as seen inFIG. 6. As explained above, movement of the valve spool is quite rapidbecause of the pressure drop across constricted portion 108a ofpassageway 108. When valve spool 105 is in this position just mentioned,communication between annular passageways 87 and 88 is prevented whilecommunication between annular passageways 86 and 87 is permitted bymeans of annular valve portion 105k. It will now be apparent that mainvacuum port 68 is in commu nication with the source of vacuum throughopening 80, annular passageways 87, 86 and passageway 111. As themarginal portion of vacuum pad 55 is in sealing engagement with thesurface of the object to be gripped during this actuation of valvemember 40, vacuum pad 55 is vacuumized through the main vacuum port forsecurely gripping the object. When it is desired to release the object,vacuum line 44 is opened to atmosphere by suitable means. This resultsin a flow of air into annular passageways 86, 87, opening 80 and themain vacuum port 68 for breaking the vacuum in the vacuum pad therebyreleasing tion illustrated in FIG. 5 under the force of spring 106 againplacing the main vacuum port in communication with the atmospherethrough breather 100. Additional air may be quickly drawn through themain vacuum port from breather to aid in releasing the grip by vacuumpad 55. Return of the valve spool and separation of the rim of pilot cup75 from the surface of the object again allows the source of vacuum tocause a small flow of air through the pilot vacuum port, therebyadapting the vacuum pad assembly for automatically gripping the surfaceof an object upon contact of the vacuum pad assembly with the surface ofthe object.

It will be realized that valve member 40 operates in a very rapid mannerfor automatically vacuumizing the vacuum pad. Movement of the valve stemis almost instantaneous upon engagement of pilot cup 75 with the surfaceof the object for closing the pilot vacuum port. As explained above,this action communicates the main vacuum port with the source of vacuumfor vacuumizing the vacuum pad assembly. Release of the object grippedis also accomplished in a quick and effective manner by valve 40. Itwill be appreciated that the above described pneumatic mean-s adaptingthe vacuum pad for automatically gripping a surface upon contact withthe same will function equally well with a flat or planar vacuum pad.

FIG. 10 illustrates in schematic form a preferred vacuum and controlsystem for the embodiment of the vacuum gripping device shown in FIG. 1.A motor powered vacuum pump of suitable construction is mounted onindustrial lift truck 20, which pump discharges to the atmospherethrough a mufller 116. Suitable air conduit means 117 are provided forcommunicating the intake port of vacuum pump 115 with flexible airconduit 34, which flexible conduit is trained over pulley 33 supportedby the upright members of the lift truck. Further conduit means 118 areprovided for communicating flexible air conduit 34 with a release valve119, which valve includes a slidable member 120 adapted to be actuatedby a solenoid 121 controlled by a switch 122. Switch 122 is located in aconvenient location on the lift truck for manip ulation by an operatorof the truck. A spring 123 is provided for returning member 120 to itsnormal position, i.e., the position of FIG. 10. Valve member 120includes a first bore 124 communicating conduit means 118 with a checkvalve 125, and valve member 120 includes a second bore 126 adapted tocommunicate the check valve with a conduit 127 when the valve member isactuated by solenoid 121. Conduit 127 opens to atmosphere through afilter 128. A conduit 130 communicates check valve with swivel 37, and aconduit 131 communicates a vacuum tank 132 with conduit 130. Thelocation of vacuum tank 132 is important for at least. two reasons.First, the tank should be located between the vacuum pad assemblies andflexible conduit 34. If breakage should occur in any of the variousconduits communicating the vacuum pad assemblies with the vacuum pump,such breakage would most likely occur in the flexible conduit which issubjected to frequent flexure and wear because of movement of thecarriage to which the flexible conduit connects. If breakage shouldoccur in flexible conduit 34 when a load is being gripped, vacuum tank132 will maintain all vacuum pad assemblies in their vacuumizedcondition for securely holding the load. The second factor to beconsidered in mounting the vacuum tank is the length of conduitextending between the tank and the vacuum pad assemblies. By having thevacuum tank mounted as close as possible to the vacuum pad assemblies,the length of the conduits extending between the tank and the vacuum padassemblies is kept to a minimum. This reduced length of conduit makes iteasier for the vacuum tank to maintain a vacuum in the vacuum padassemblies upon failure of the vacuum pump or breakage in the conduitsextending between the tank and the pump.

The operation of the vacuum and control system of FIG. 10 is as follows:

Pump 115 is operated resulting in vacuumizing tank 132 and causing asmall flow of air through the pilot cups of the vacuum pad assemblies.As explained above, upon engagement of one of the pilot cups with thesurface of an object to be gripped, the corresponding vacuum padassembly automatically grips the object. As each vacuum pad assemblyinclude a pilot cup and valve member, each assembly independently andautomatically grips a particular surface upon contact with the same. Itwill be apparent that if one of the pilot cups is not contacted by thesurface of an object to be gripped, the valve member of thecorresponding vacuum pad assembly will not be actuated. When an operatordesires to release a load gripped by one or more of the vacuum padassemblies, switch 122 is closed thereby energizing solenoid 121 toactuate valve member 120 for simultaneously placing the various conduitsin communication with the vacuum pad assemblies in communication withthe atmosphere through filter 128.

Indicating means are provided for indicating to an operator of theindustrial lift truck the pressure in each of the vacuum pad assemblieswhen the latter are gripping the surface of an object. Such means are inthe form of four pressure gauges 135, 136, 137 and 138. Pressure gauge135 is placed in communication with the vacuum pad of vacuum padassembly 14 for indicating the pressure therein by conduits 139 and 140,which conduits communicate with each other through a junction block 141.Pressure gauge 136 is in communication with the vacuum pad of vacuum padassembly 15 for indicating the pressure therein by means of conduits 142and 143, which conduits communicate with each other through junctionblock 141. It will be understood that conduits 140 and 143 each have oneend thereof communicating with small openings (not shown) in the vacuumpads of respective vacuum pad assemblies 14, 15. Similarly, pressuregauge 137 is in communication with the vacuum pad of vacuum pad assembly18 by means of a conduit 145, and pressure gauge 138 is in communicationwith the vacuum pad of vacuum pad assembly 19 by means of a conduit 146.It will be understood that conduits 145 and 146 each have one endthereof in communication with small apertures (not shown) located in thevacuum cups of respective vacuum pad assemblies 18 and 19. Pressuregauges 135-138 are mounted on the backside of plate 12 for easy viewingby an operator of the lift truck during operation of the latter. Thepressure gauges provide a ready indication for indicating the vacuum padassemblies being vacuumized upon contact with the surface of an objectto be gripped. Further, the pressure gauges serve as a ready means forindicating to an operator of the lift truck whether the various vacuumpad assemblies are operating properly.

FIG. 11 shows a modified valve member 40 for use with the vacuum padassemblies of the vacuum gripping device of this invention. Theconstruction of modified valve is the same in all respects with valvemember 40 previously described with the exception of cover plate 90 atone end of the valve member. In the modified form of valve member,designated 40', a cover plate 90', is provided, which cover plate has acentral aperture 148 opening into recess 107. Aperture 148 is internallythreaded for threading engagement with one end of a line or conduit 149.As will be explained further hereinbelow, vacuum line 149 extends to arelease valve. The release valve is normally closed for closing aperture148, and the release valve is adapted to open line 149 to atmosphere foradmitting air to the end of bore 85 adjacent cover plate 90. If line 149is opened when valve member 40 is in its gripping position, air Will beadmitted to the end of the bore adjacent cover plate 90 for quicklyreleasing the valve spool to its non-gripping or normal position. In themodified valve, the main vacuum line is not opened for releasing thesurfaces gripped. It will be noted that when valve spool of valve member40 returns to its normal position, all air admitted to vacuum pad 55 forbreaking the vacuum therein is drawn in through breather 100. Thereleasing action of the vacuum pad assembly having the modified form ofvalve member 40' associated therewith is very quick in operation asconduit 149 is rather small in diameter providing a conduit of rathersmall volume extending between valve member 40' and the release valve.Because of this small volume a reduced amount of air is required to passthrough conduit 149 for being admitted to the modified valve member torelease the valve spool therein for return to its normal or non-grippingposition.

FIG. 12 schematically shows a preferred vacuum and control system forthe embodiment of the invention shown in FIG. 1 and employing themodified valve members. In FIG. 12 all components of the main vacuumline are the same except a release valve is not located in the mainvacuum line. Modified valve members 41', 42' and 43', which valvemembers are identical to valve member 40', have respective conduits 150,151 and 153 corresponding with conduit 149, Conduits 149 and 150communicate with each other and with a conduit 153, the latter conduitbeing in communication with a modified swivel 37. Conduits 151 and 152communicate with each other and with a conduit 154, which last mentionedconduit also communicates with the modified swivel. A small releasevalve 156 has a valve member 157 slidable therein, which valve member isadapted to be actuated by a solenoid 158 energized by a switch 159. Aspring 160 engages one end of the valve member for urging the same intothe position shown in FIG. 12. Valve member 157 includes a bore 161,which bore is adapted to communicate a conduit 162 with a conduit 163when the valve member is actuated by solenoid 158. Conduit 162communicates with the atmosphere through a filter 164, and conduit 163extends to swivel 37 for communication with conduits 153 and 154. In thevacuum and control system illustrated in FIG. 12, the operation of thevarious vacuum pad assemblies is the same as described above forgripping the surface of an object to be handled. However, release of theload is accomplished by actuation of valve 156 by closing switch 159.Actuation of this valve opens conduit 163 to atmosphere which results inopening the ends of the modified valve members adjacent cover plate 90to atmosphere for quick actuation of the valve members. As will beapparent from FIG. 12, it is not necessary to open the main vacuum lineextending to the various vacuum pad assemblies for releasing a load. Itis only necessary to open the relatively small diameter conduits whichcommunicate with release valve 156, which release valve itself may bemuch smaller in size than the release valve of FIG. 10. As explainedabove, release of an object gripped by the vacuum pad assemblies havingthe modified valves associated therewith is much quicker because of thesmaller conduit volume that must be filled with air for actuation of thevalve members to their normal or non-gripping position.

FIG. 13 schematically illustrates a vacuum gripping device employing amodified vacuum pad assembly. The modified vacuum pad assembly differsfrom the vacuum assembly of FIGS. 1 through 12 in that the former doesnot employ valve member 40 or 40' for communicating the main vacuum portwith a source of vacuum when the pilot vacuum port is covered by thesurface to be gripped. The modified vacuum pad assembly of FIG. 13utilizes, in lieu of valve member 40 or 40', a valve arrangementincluding a conventional valve adapted to be actuated by a solenoid foralternately communicating the main vacuum port with atmosphere and witha source of vacuum. A vacuum switch of conventional design is providedfor energizing the solenoid. Passageway means in the form of a vacuumline communicates the pilot vacuum port with the source of vacuum, andthis vacuum line has a section of relatively small diameter along thelength thereof, this section generally corresponding to constrictedportion 108a of valve member 40. The vacuum switch is connected in thevacuum line between the pilot vacuum port and the section of relativelysmall diameter. When the pilot vacuum port is covered by a particularsurface to be gripped, the vacuum line and vacuum switch are vacuumizedthereby energizing the solenoid for actuation of the valve. When thevalve is actuated, the main vacuum port is placed in communication withthe source of vacuum pad for gripping the surface.

Referring now to FIG. 13, the vacuum gripping device employing themodified vacuum pad assemblies will be seen to be identical inconstruction, between mulfer 116 and swivel 37, to the vacuum grippingdevice illustrated in FIGS. 1 through 10. In FIG. 13 only two modifiedvacuum pad assemblies are illustrated. However, it will be under-stoodthat any suitable number of modified vacuum pad assemblies may beemployed depending on the size and shape of the gripping device. Thevacuum gripping device illustrated in FIG. 13 is shown with two modifiedvacuum pad assemblies, generally designated 170 and 171. As both of themodified vacuum pad assemblies are of identical construction, only onewill be described in detail.

Modified vacuum pad assembly 170 includes vacuum pad 55 having mainvacuum port 68 and pilot vacuum port 72 with pilot cup 75 associatedtherewith. A conduit 172 communicates the main vacuum port with a valve173, which valve may be of conventional design including a slidablemember 174 having through passageways 175 and 176. The slidable memberis normally held by a spring 177 for communicating conduit 172 with aconduit 178 via passageway 175. Conduit 178 opens to atmosphere througha filter or breather 179. A solenoid 180 is provided for sliding member174 against spring 177. When solenoid 180 is energized, member 174 ismoved for communicating conduit 172 with a conduit 182 via passageway176. Conduit 182 communicates the modified vacuum pad assembly withswivel 37 and the source of vacuum. A vacuum switch 183 of conventionalconstruction is provided for energizing solenoid 180. The vacuum switchreceives electrical power from a suitable source, such as battery 184.

The modified vacuum pad assembly includes passageway means in the formof a vacuum line 186 extending between the pilot vacuum port and conduit182 for communicating the pilot vacuum port with the source of vacuum.Vacuum line 186 includes a section 186a of relatively small diameter,which section generally corresponds to constricted portion 108a of valvemember 40. Section 186a may be formed in any suitable manner. Forexample, vacuum line 186 may be crimped or squeezed to provide arelatively small diameter portion or a suitable fitting may be connectedin vacuum line 186, which fitting is provided with a relatively smalldiameter bore. Vacuum switch 183 opens into vacuum line 186 betweenpilot vacuum port 72 and section 186a. Because of relatively smalldiameter section 186a, the flow of air from atmosphere through pilotvacuum port 72 is not substantial. By reason of section 186a, pump 115is not burdened to any extent in maintaining the main vacuum conduitssubstantially vacuumized when the system is opened to atmosphere at thepilot vacuum ports, i.e., when one of the pilot cups is not in contactwith a surface to be gripped. Vacuum line 186 itself is preferably ofsmall diameter and has the shortest possible length for providing aspace of minimum volume that must be vacuumized when the pilot cup iscovered for actuating the vacuum switch, thereby insuring rapidoperation of the modified vacuum pad assembly.

The operation of the vacuum gripping device employing the modifiedvacuum pad assemblies is as follows:

Pump is operated thereby resulting in vacuumizing tank 132 and conduits182 and causing a small flow of air through the pilot vacuum cups of themodified vacuum pad assemblies. When one of the pilot cups is closed bya particular surface to be gripped upon contact with the latter by thevacuum pad, vacuum line 186 is quickly vacuumized thereby vacuumizingand actuating vacuum switch 183. Actuation of the vacuum switchenergizes solenoid thereby actuating valve 173 for sliding movablemember 174 to a position where passageway 176 communicates conduits 172and 182. This movement of the valve results in communicating the mainvacuum port 68 with the source of vacuum thereby vacuumizing the vacuumpad itself for gripping the object having its surface covering pilot cup75.

When it is desired to release the object, switch 122 is closed therebyactuating release valve 119 for communicating simultaneously allmodified vacuum assemblies with the atmosphere through filter 128. Whenthis occurs, the pilot cup is again uncovered thereby allowingresumption of the small flow of air through vacuum line 186 which inturn results in opening of the vacuum switch. Opening of the vacuumswitch results in deenergizing solenoid 180 thereby allowing movablemember 174 to be returned by spring 177 for again communicating the mainvacuum port with the atmosphere through breather or filter 179.

The modified vacuum pad assembly has the marked advantage of beingpositive in operation. When the pilot vacuum port is covered forvacuumizing line 186 and vacuum switch 183, solenoid 180 is energizedthereby positively moving the movable member of the valve forcommunicating main vacuum port with the source of vacuum.

From the foregoing description it is believed to be apparent that thisinvention provides an improved vacuum gripping device having at leastone vacuum pad assembly adapted for automatically gripping a particularsurface upon contact with the same. Further, it will be apparent fromtheforegoing that this invention provides vacuum gripping means including aplurality of separate vacuum pad assemblies wherein each vacuum padassembly is adapted to grip independently and automatically a particularsurface upon contact with the same. It will also be apparent that theinvention provides an improved vacuum pad for gripping curved surfaces.

While the invention has been shown in only several forms it will beobvious to those skilled in the art that it is not to be so limited, buton the contrary the invention is susceptible of various changes andmodifications without departing from the spirit and scope of theappended claims. For example, while only one pilot vacuum port andassociated pilot cup are shown with each vacuum pad, it will be realizedthat, if desired, a number of pilot vacuum ports and pilot cups could beoperatively associated with the vacuum pad. If a number of pilot vacuumports are used, they may be equally spaced around the periphery of thevacuum pad closely adjacent the sealing ring thereof and placed incommunication with a source of vacuum by suitable passageways, conduits,etc. By such construction, the vacuum pad would not grip a particularsurface until the sealing ring and the surface were in substantialco-extensive contact. As a further modification coming within the .scopeof the appended claims, the pilot cups might be formed as an integralpart of the sealing ring for the vacuum pad.

I claim:

1. Vacuum gripping means comprising, at least one vacuum gripping padassembly including a vacuum pad having sealing means extending aroundthe periphery of the pad, said sealing means including a flexible ringmember secured to said pad and extending continuously around theperiphery of the same, which flexible ring member is generally U-shapedin cross-section having inner and outer lips each being in sealingengagement with said pad, a resilient ring member secured to said padand extending continuously around the periphery of the same within saidflexible ring member, said flexible ring member having the bight portionthereof in spaced relation with said resilient ring member, whereby saidflexible ring member readily conforms to the contour of a surface to begripped upon initial contact with the same and said resilient ringmember limits flexing of the flexible ring upon vacuumizing of thegripping pad. assembly.

2. The structure according to claim 1 wherein said flexible ring memberis formed of neoprene and wherein said resilient ring member is formedof a sponge-like material.

3. Vacuum gripping means comprising, at least one vacuum gripping padassembly including a vacuum pad having a gripping face curved to receivethe curved surface of a cylindrical object to be gripped, sealing meansextending around the periphery of said face, said sealing meansincluding a flexible ring member secured to said pad and extendingcontinuously around the periphery of said face, which flexible ringmembers is generally U-shaped in cross-section having inner and outerlips each being in sealing engagement with said pad, a resilient ringmember secured to said pad within said flexible ring member andextending continuously aroung the periphery of said face, said flexiblering member having the bight portion thereof in spaced relation withsaid resilient ring member, whereby said sealing means readily conformsto the shape of the curved surface of said object and to the shape ofsaid face at the periphery thereof for forming an effective seal betweensaid pad and said surface.

4. The structure according to claim 3 wherein said flexible ring memberis formed of neoprene and wherein said resilient ring member is formedof a sponge-like material.

5. Sealing means for a vacuum gripping pad comprising, a flexible ringsecured to the gripping face of said pad and extending continuouslyaround the pad adjacent the periphery thereof, said ring being generallyU-shaped in cross section thereby defining inner and outer continuouslips, which lips sealingly engage said face of the pad thereby defininga closed generally annular space within said ring, a resilient ringsecured to said face of said pad and extending continuously around theperiphery thereof within said space, said flexible ring having the bightportion thereof in spaced relation with said resilient ring, wherebysaid flexible ring readily conforms to the contour of a surface to begripped upon initial contact with the same and said resilient ringlimits flexing 0f the flexible ring upon vacuumizing of the grippingpad.

6. In combination, a vacuum gripping pad having a gripping faceincluding spaced, inner and outer grooves extending continuously aroundthe pad adjacent the periphery thereof, a flexible ring having aU-shaped cross section defining inner and outer continuous lips receivedin said grooves, respectively, said lips each having continuous portionsextending toward each other, a substantially rigid retaining ringsecured to said face of the pad within said flexible ring, which ringhas its marginal portions engaging said continuous portions thereby tosecure said flexible ring to said pad, a resilient ring substantiallycoextensive with said retaining ring and secured to the latter, saidflexible ring having the bight portion thereof in spaced relation withsaid resilient ring, whereby said flexible ring readily conforms to thecontour of a surface to be gripped upon initial contact with the sameand said resilient ring limits flexing of the flexible ring uponvacuumizing of said gripping pad.

References Cited by the Examiner UNITED STATES PATENTS 2,347,491 4/ 1944Lente 29464 2,578,220 12/1951 Billner 294-65 2,665,013 1/1954 Socke.2,887,849 5/1956 Lytle. 2,893,581 7/1959 Cushman 214-651 2,899,0888/1959 Corbin 214-651 X 2,934,086 4/1960 Blatt 294-64 X 2,942,745 6/1960Horton 214650 2,999,715 9/1961 Firestone 29464 3,089,723 5/1963 Fortsonet a1. 29465 FOREIGN PATENTS 396,668 3/1923 Germany. 845,835 8/1960Great Britain.

HUGO O. SCHULZ, Primary Examiner. MORRIS TEMIN, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,219,379 November 23, 1965 Victor H. Ames It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 3, line 52, for "griping" read gripping column 4, line 40, for"on" read one column 5, line 10, for "wringles" read wrinkles column 11,line 15, before "pad" insert thereby vacuumizing the vacuum line 48,after "as" insert a column 13, line 25, for "members" read member Signedand sealed this 20th day of September 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Arresting Officer Commissioner ofPatents

5. SEALING MEANS FOR A VACUUM GRIPPING PAD COMPRISING, A FLEXIBLE RING SECURED TO THE GRIPPING FACE OF SAID PAD AND EXTENDING CONTINUOUSLY AROUND THE PAD ADJACENT THE PERIPHERY THEREOF, SAID RING BEING GENERALLY U-SHAPED IN CROSS SECTION THEREBY DEFINING INNER AND OUTER CONTINUOUS LIPS, WHICH LIPS SEALINGLY ENGAGE SAID FACE OF THE PAD THEREBY DEFINING A CLOSED GENERALLY ANNULAR SPACE WITHIN SAID RING, A RESILIENT RING SECURED TO SAID FACE OF SAID PAD AND EXTENDING CONTINUOUSLY AROUND THE PERIPHERY THEREOF WITHIN SAID SPACE, SAID FLEXIBLE RING HAVING THE BIGHT PORTION THEREOF IN SPACED RELATION WITH SAID RESILIENT RING, WHEREBY SAID FLEXIBLE RING READILY CONFORMS TO THE CONTOUR OF A SURFACE TO BE GRIPPED UPON INITIAL CONTACT WITH THE SAME AND SAID RESILIENT RING LIMITS FLEXING OF THE FLEXIBLE RING UPON VACUUMIZING OF THE GRIPPING PAD. 